Generally, a mobile terminal is an electronic device that allows a user to perform wireless communication, access a network, receive a digital broadcast, and so forth, regardless of time and place. Recently, mobile terminals have been developed to perform functions such as communication, Internet access, digital broadcast reception, and document creation, gaming, and the like.
Mobile terminals are gradually miniaturized and thinned to meet the needs of customers. Complying with this trend, interest in novel input devices is increasing to reduce a large volume of existing push-button input devices. Particularly, a new input method using a touch screen, remarkably different from the existing input method, attracts user attention.
Generally, a touch screen is one of the input devices that provide an interface between an information communication device using a display unit and a user. When the user directly touches a screen with an input device, such as a finger, a pen, or some other input device, the interface between the information communication device using a display unit and the user is activated. Because anyone can easily use the touch screen simply by touching the display unit with input tools, such as a finger, pen, and the like, the touch screen is applied to various devices such as an automated teller machine (ATM), a personal digital assistant (PDA), a mobile phone, and so on and in various sites such as banks, government and public offices, tour and traffic guides, and so forth.
There are various types of touch screens such as resistive, capacitive, ultraonic, infrared, and surface acoustic. Among the touch screens, the resistive type touch screen, which is cheap and to which various input tools such as a finger, a pen, and the like may be applied, is mainly used.
In the mobile terminal including the touch screen, when the user puts the mobile terminal to his/her ear to talk, the ear or cheek of the user presses the touch screen of the mobile terminal so that the touch screen may often malfunction. Therefore, a proximity sensor senses approach of the ear or cheek to the touch screen to prevent malfunction of the touch screen.
Commonly, the upper part of the proximity sensor is covered with a plane lens or a glass sheet. Because the plane lens and the glass sheet are made of transparent materials, light emitted from the proximity sensor is diffusively reflected from the surface or the inside of the plane lens and the glass sheet so that the proximity sensor malfunctions and erroneously senses the diffused reflection as the ear or cheek of the user approaching the touch screen. To solve this problem, power of the light emitting unit of the proximity sensor has to be reduced, but distance of sensing an external object is also shortened due to the reduced power.
Therefore, there is a need for a sensing device using a proximity sensor that senses an approaching external object in which malfunction of the proximity sensor is prevented and a mobile terminal having the same.